The long-term objective of this project is to reduce future human exposure to toxic chemicals through the development and application of thermal techniques for removing, immobilizing, or detoxifying contaminants found in a range of subsurface environments. The specific aims are: 1. investigate the range and effectiveness of application of steam enhanced extraction to remove volatile contaminants from highly heterogeneous soils and aquifer systems. 2. Examine the effects of temperature on the soil microbial populations and the potential for temperature-enhanced contaminant biodegradation and immobilization rates. 3. Determine the effectiveness of the co-injection of air, oxygen, or carbon dioxide with steam to enhance precipitation, immobilization, and mobilization rates of toxic metals in aqueous or non-aqueous phases. These aims will met by laboratory, theoretical, an numerical studies which complement other field projects focussed on demonstrations of innovative cleanup technologies at specific sites at Alameda Naval Air Station and elsewhere. Our goals are the generalization of laboratory and site- specific research finding, improvements in the design an operational strategy of thermally enhanced restoration processes, and technology transfer to the restoration industry.